Regarding cheap computers, I wouldn't bother reading the printed
classifieds.  The paper charges some $80 to do the weekend ads, so
you'll be paying for that by proxy when you buy the computer.  Also,
consider that you can generally buy a new cheap computer for under $500
at the major retailers, consistently.  Walmart sells (or used to?)
Linspire boxes on the cheap; a great way to get started with Linux.  Not
sure I would buy from Walmart on moral principle, but it is an optinon.

There are local white-box makers, too.  General Nanosystems
(http://nanosys1.com/) and Tran Micro on University Avenue have pretty
nice little starter systems, sans monitor, in the $300-400 range.  I've
got a 13" and a 17" monitor I'm not using.  One of these days, I'm going
to replace the 19", too, so I'll make that available to the TCLUG
members off our classifieds site.

And there's the segway...  If you have less to spend, first look at the
TCLUG classifieds site.  People are giving away free computers or cheap
computers all the time.  One of these days, I'll be going through my
junk and listing everything there for free.  I've got a couple old
pentium II's I'll probably be getting rid of some time.  I have a couple
cases to get rid of.  I've got an old UltraSparc 5 I'm not using, though
perhaps OpenSolaris 10 might work nicely on it (I've had issues with
Linux on it).

The next stop is Craig's List.  It's free.  You won't be paying for the
seller's listing fees; there are none.  Etc.

Where else.  I think there was a local company that purchases old
systems off of companies and sells them cheaply.  The URL was posted to
this list a while back.

Anyway, you get the idea.  Good luck!